Something went wrong with Gukesh's preparation. Black has several moves to choose from that give him a comfortable position.
15... f6h5 A good move, preparing either to exchange White's bishop after g7-g5 or to activate the knight with Nh5-f4. 16. a1e1  16... e8f8  17. g2g4 A new move. 17... h5f4 